Do you calculate head loss if completely submerged?

[jasonrusso]

I replaced the return pump on my AIO. The sump is in the rear chamber. The complete return is about 12" and completely submerged when running. I'd think that head loss would be zero because the water level wants to be in the return pipe anyway.

Any thoughts?

 

[JoshH]

I replaced the return pump on my AIO. The sump is in the rear chamber. The complete return is about 12" and completely submerged when running. I'd think that head loss would be zero because the water level wants to be in the return pipe anyway.

Any thoughts?

You are correct, aside from minor frictional losses (So small it's not even worth computing) there is near zero head loss with your setup

 

[DCR]

It is never zero. I would probably assume at least about 1-2 ft just for the short distance and the exit loss.